Nodelists as values

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While we're getting our wishlist out (see Norm's previous posting) for
obscure facilities which we need for pipelines we're writing, I've
finally been converted to the restricting-values-to-strings-is-crazy
position.

My problem:  I have a large complex file (the metadata for the XML
Schema test collection) which includes in some but not all cases a
sequence of elements which carry in their xlink:href attributes the
URIs of schema documents which are needed for the test.

I want to pass these URIs around in a way which will allow them to be
iterated over to produce a sequence of schema documents.

At the moment this is not possible, as far as I can tell (if you can
figure out a workaround, e.g. how to convert a space-separated list of
URIs into a sequence of documents, _please_ let me know).

But if we had nodesets as values, I could just pass the set of
attribute nodes as an option.

But here's why we're _not_ going to do this in V1:  it would take a
substantial amount of work to decide how to get things _back_ from
such values.  Would we allow, e.g.,

 <p:declare-step type="my:demo">
  <p:output name="result" sequence="true" primary="true"/>
  <p:option name="attrSet"/>

  <p:identity select="$attrSet"/>
  <p:for-each>
   <p:load>
    <p:with-option name="href" select="."/>
   </p:load>
  </p:for-each>
 </p:pipeline>

To be useful, such a pipeline would need to be allowed.  But that's
too big a change for this late in the game. . .

ht
- -- 
       Henry S. Thompson, School of Informatics, University of Edinburgh
                         Half-time member of W3C Team
      10 Crichton Street, Edinburgh EH8 9AB, SCOTLAND -- (44) 131 650-4440
                Fax: (44) 131 651-1426, e-mail: ht@inf.ed.ac.uk
                       URL: http://www.ltg.ed.ac.uk/~ht/
[mail really from me _always_ has this .sig -- mail without it is forged spam]
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Received on Tuesday, 1 December 2009 11:25:11 UTC